Runaway memory crash

With all extensions disabled and only speed dial open, one of the Opera processes increases consumption of RAM until a crash occurs within a two minutes. Crashreporter log is saved, but as an empty file.

This first occurred with Stable, a week or two ago. Re-installing into a new folder didn't help so I've been using Developer, which has been OK until today. All extensions have now been removed, and it's still happening.